A High-Performance 3D Imaging Technique Using Simultaneous Azimuth and Elevation Compounding

A new technique for 3D imaging with a row-column array configuration has been developed. The technique requires an electrostrictive piezoelectric for the active substrate. While the top set of electrodes are connected to RF transmit and receive channels for conventional diverging wave imaging, the orthogonal bottom set of electrodes are connected to independently controlled variable DC bias channels. By implementing modulated bias patterns compounded across multiple pulses, fine delay control across the bottom elements can be achieved simultaneously to imaging with the top set of electrodes. This resulted in a high-quality 2-way focus in both azimuth and elevation. A 20 MHz electrostrictive composite substrate was fabricated and 64 top by 64 bottom electrodes were patterned and connected to custom beamforming and biasing electronics. The point spread functions were generated in all dimensions and the -6 dB resolution was measured to be 93 μm axially, 272 μm in the azimuth, and 328 μm in the elevation dimension. This was in good agreement with the simulated resolutions of 80 μm, 273 μm, and 280 μm respectively.